In modern high-performance automatic bobbin winders, the change of bobbins is carried out without interrupting the supply of yarn. In a known bobbin winding machine such as that disclosed in U.S. Pat. No. 4,969,607 (corresponding to Swiss Patent Application No. CH-A-677781), two rotatable pegs or spindles are mounted on a revolver or turret, and holders for the bobbins may be attached to such spindles. After a predefinable yarn quantity is wound on a bobbin on one of the spindles, that spindle is removed from the winding position to a changing or standby position by a partial rotation of the revolver. During the rotation of the revolver, the empty bobbin on the second spindle reaches the winding position.
During this process, the incoming yarn to be wound is still supplied continuously. The yarn leading to the full bobbin is deflected to yarn catching and severing means, such as a slot on the empty bobbin provided with a knife or cutter, by means of yarn changer apparatus which can be pivoted from the side between the empty bobbin and the full bobbin, so that said yarn is grasped by the yarn catcher knife and separated. The separated end on the full bobbin, which continues to rotate after the separation due to its inertia, beats on the driven empty bobbin (now in the winding position) during each rotation. This leads to the danger that the loosely whizzing yarn end could get entangled with the yarn supplied to the now empty bobbin.
In order to prevent this, separating means may be introduced from the side of the bobbin away from the yarn changer apparatus into the area of the surface of the full bobbin in order to prevent the projecting whizzing yarn end from coming into contact with the empty bobbin. In order to carry out the protection effectively, the separating apparatus must be of a certain dimension. This, however, leads to the effect that a lot of space is required to bring the separating apparatus, when it is not required, into a position where it will not interfere with the desired building and moving of the yarn packages, since the separating means must be kept outside of the bobbin being built up and outside of the already full bobbin pivoting with the revolver during the change of the bobbin.